If at any time you lost something while travelling in a TTC bus, after you got off the bus. You need to immediately wait for the next bus in the same route and then ask that bus driver to phone it in to the control unit and inquire about the lost item in the front bus that just left. Do not delay approaching the next bus driver for help, before other people in the bus finds the item and takes it away. Some people are very honest and would return the lost item to the bus driver. Once i saw someone return a big Ipad tablet that he found in a back seat of the bus.
If the bus driver happened to have your lost item in possession at the time when control unit calls him on the bus phone, they would arrange a meeting in such a way for you to retrieve your lost item in certain specific intersections roads. In such case, your bus driver (The one you approached for help) will tell you where to wait for the other bus and what bus number it will be (Bus numbers are four digit written in front center of the bus, at the top right corner and top left corner, also at the center of the back of the bus). Do not be impatient and leave the intersection you were told to wait. Once the bus arrives, you would be asked to identify your lost item such as description color, size, material. It doesn't have to be exact description because not everyone can remember all items clearly and the bus driver understands this. If you answered correctly even though vaguely, you will be given your lost item back.
Just in case, the meeting could not be arranged to retrieve your lost item or that you left the mentioned intersection road without waiting for the bus because you were in a hurry to leave, you can always call the TTC customer service number 416-393-4636 and tell them you lost an item in the bus. You will be asked to go to Bay station, that's where the lost and found office is located. But you will have to wait for a couple of days before you can go there because it takes time for the bus driver to hand over the lost item to the division, and then the lost item makes its way to the lost and found bay station office.